Shader "UI/UIImageRoundCorner"
{
	Properties
	{
		[PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
		_Color("Tint",Color) = (1,1,1,1) 

		_StencilComp("Stencil Comparition",Float) = 8
		_Stencil("Stencil ID",Float) = 0
		_Stencil("Stencil Operation",Float) = 0

		_StencilWriteMask("Stencil Write Mask",Float) = 255
		_StencilReadMask("Stencil Read Mask",Float) = 255

		_ColorMask("Color Mask",Float) = 15

		[Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip("Use Alpha Clip",Float) = 0

		_RoundedRadius("Rounded Radius",Range(0,256)) = 64

	}
	SubShader
	{
		Tags{
			"Queue" = "Transparent"
			"IgnoreProjector" = "true"
			"RenderType" = "Transparent"
			"PreviewType" = "Plane"
			"CanUseSpriteAltas" = "True"
		}
		Stencil{
			Ref[_Stencil]
			Comp[_StencilComp]
			Pass[_StencilOp]
			ReadMask[_StencilReadMask]
			WriteMask[_StencilWriteMask]
		}
		// No culling or depth
		Cull Off
		Lighting Off 
		ZWrite Off 
		ZTest[unity_GUIZTestMode]
		Blend SrcAlpha OneMinusSrcAlpha
		ColorMask[_ColorMask]

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			#include "UnityCG.cginc"
			#include "UnityUI.cginc"

			struct appdata_t
			{
				float4 vertex : POSITION;
				float4 color : Color;
				float2 texcoord : TEXCOORD0;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
				fixed4 color : Color ;
				half2 texcoord : TEXCOORD0 ;
				float4 worldPosition : TEXCOORD1 ;  
			};

			fixed4 _Color;
			fixed4 _TextureSampleAdd;
			float4 _ClipRect;
			float _RoundedRadius; 
			float4 _MainTex_TexelSize;

			v2f vert(appdata_t IN){
				v2f OUT;
				OUT.worldPosition = IN.vertex;
				OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);
				OUT.texcoord = IN.texcoord;
				#ifdef UNITY_HALF_TEXEL_OFFSET
				OUT.vertex.xy += (_ScreenParams.zw-1.0) *float2(-1,1);
				#endif
				OUT.color = IN.color*_Color;
				return OUT;
			}

			sampler2D _MainTex;

			fixed4 frag (v2f IN) : SV_Target
			{
				half4  color = (tex2D(_MainTex,IN.texcoord)+_TextureSampleAdd)*IN.color;
				color.a *= UnityGet2DClipping(IN.worldPosition.xy,_ClipRect);
				#ifdef UNITY_UI_ALPHACLIP
				clip(color.a-0.001);
				#endif

				float width = _MainTex_TexelSize.z;
				float height = _MainTex_TexelSize.w;

				float x = IN.texcoord.x * width;
				float y = IN.texcoord.y * height;
				float r = _RoundedRadius;

				//zuo xia jiao 
				if (x < r && y < r)
				{
					if((x-r)*(x-r)+(y-r)*(y-r)>r*r) color.a = 0;
				}

				//zuo shang jiao
				if (x < r && y > (height-r))
				{
					if((x-r)*(x-r)+(y-(height-r))*(y-(height-r))>r*r) color.a = 0;
				}

				//you xia jiao
				if (x > (width - r) && y < r)
				{
					if((x-(width - r))*(x-(width - r))+(y-r)*(y-r)>r*r) color.a = 0;
				}

				//you shang jiao 
				if (x > (width - r) && y > (height-r))
				{
					if((x-(width - r))*(x-(width - r)) +(y-(height-r))*(y-(height-r))>r*r) color.a = 0;
				}

				return color;

			}
			ENDCG
		}
	}
}
